Plant for bleaching and like purposes



.July 1927 c. B. THORNE PLANT FOR BLEACHING A D LIKE PURPOSESSheets-Sheet 1 Filed Dec. 15, 1924 Union" u u IN vnwr x Jr-rarne v willJuly 1927 c. B. THORNE PLANT FOR- BLEACHING AND LIKE PURPOSES Filed Dec.13. 1924 ZS hfis-Sheet 2 IllllllIl-l Fbtented July 5, 1927. I

UNITED STATES,

OABL BUSGH THORNE, OF HAWKESBUBY, ONTARIO, CANADA.

PLANT FOR IBLEACHING AND LIKE PURPOSES.

Application filed December 13, 1924. Serial No. 755,691.

The invention relates to a plant for bleachmg and like purposes asdescr1bed n the present specification and illustrated in theaccompanying drawings that form part of the same.

The invention consists essentlally of the novel features of constructionpointed out broadly and specifically in the claims for novelty followinga description containing an explanation in detail of an acceptable formof the invention.

The objects of the invention are to produce a superior quality of pulpsuch as 1s required for the many purposes to Wl11Cl1 that product is atpresent applied 1n the manufacture of paper, silk, and various articlesof commerce; to evenly distribute the bleaching liquor throughout themass of pulp and at the same time save the fibre from deleteriousinfluences of accumulations liable to destroy .its physical properties;to effect the operation of bleaching in a simple manner and therebyincrease the efficiency of a mill; to facilitate the manufacture of'thenumerous productions made from pulp; to insure uniformity in the colorof the bleaching; and generally to provide a bleaching applicable inmany directions in which the mass will be properly penetrated and thebleaching perfectly distributed. In the drawings Figure 1 is adiagrammatic view showing the preferable means employed.

Figure 2 is a diagrammatic View showing a modification of the meansemployed.

Figure 3 is a detail of the aerating tank in the means illustrated inFigure 1.

Figure 4 is a detail of the means illustrated in Figure 2 showing theaerating tank.

Like numerals of reference indicate corresponding parts in the variousfigures.

Referring to the drawings, the mixer 5 is preferably formed of a casingcircular in cross section and having an inlet 6 at the small end leadingthrough the top thereof and outlet 7 at the larger end leading throughthe bottom thereof and adjacent to the inlet the hot water inlet 8 andbleaching liquor inlet 9.

The shaft 10 is journalled in suitable bearings in the heads of mixer 5and carries a pulley 11, which is connected to the power installationadapted to run the plant.

The paddles or stir-about sticks 12 proough penetration and distributionof the bleaching liquor Without, destroying its physical propertieswhich is liable to happen under some conditions of handling, especiallyif the pulp is of a dense nature for then stirring is about the only wayof mixing without injuring the fibrous nature of the substance.

The bleaching liquor head box 13 is situated at an elevation in relationto the mixers 5 and is formed with the inlet 14 and outlet 15 and theoverflow outlet 16, the inlet 14 being adjacent to the lower end andconnected to the supply by the piping 17, the overflow outlet 16emptying through. the piping 18 and the outlet 15 being connected by thepiping 19 to the measuring box 20 and having the control valve 21 insaid piping 19.

The measuring box 20 is a well known device and is formed in theinterior to empty the liquid at a predetermined level into the piping22, which leads to the bleaching liquor inlet 9 to the mixer 5, therebyfurnishing the bleaching liquor to the pulp just asit reaches themixer-s.

The hot water head box 23 is connected to a hot water supply by thepiping 24 leading to inlet at the upper end the overflow outlet andpiping 25 being adjacent and through the side wall.

At the opposite end the piping 26 joins the head box 23 to a measuringbox 27, which is joined to the hot water inlet 8 of the mixer 5 by thepiping 28, thereby furnishing heat and water to accompany the bleachingliquor to the pulp after it reaches the mixer.

The chute 29 leads from the mixer outlet 7 to the tank, tower or vat 30which has the inlet 31 through the upper and smaller end 32 and theoutlet 33 through the lower or larger hopper bottom 34, from which thechute 35 leads to the combined washer and thickener 36. The outlet 38 ofthe washer tank 46 having a chute therefrom .eventuall leading to thewasher stock chest,

The vertical shaft 47 extendsupwardly and centrally through thetanks 46,42 and 30 and is journalled in suitable bearings and at its lower enddriven through the gears 49 and 50 rotated by the shaft 38 connected toa suitable motor. This. shaft 47 is hollow and inside eachtank has oneor more outlets for air, gasor other fluid and ,at its upper end isconnected to the stat onary pipe 51 through the coupling 52, th sstationary pipe .51 leading from a tank 53 here shown as fed from an aircompressor 54, though naturally other gaseousfiuids in liquids may befed to the tank 53 according to the articular process to be carried out,but to give a clearer understanding of the inventionthis description ismore particularly confined to the use of air in bleaching pulp.

The interior of the tanks 30, 42 and 46 arethe same, so the descriptionwill cover the three or more where used, besides one may be sufficientfor some purposes.

The nozzle 55 extends from the sleeve 56 fixedly mounted on the shaft 47and is formed with perforations 57 and preferably curved.

This nozzle 55 turnswith the shaft and passes throufgh the dense pulpand the compressed. air ows swiftly through the perforations into thepulp mass and percolates therethrough driving out the accumulations ofdecomposition gases. I The nozzle 55 is situated intermediate of theheight of the shaft 47 within a tank prefpulp has the shaft 47 andprojects in the opposite di-' rection to the nozzle 55, and is intendedto scrape the hopper bottom 34 and keep the pulp moving to the centraloutlet 35 and 33.

In Figures 2 and 4 another form of tank is shown and this tank 62 may besquare orrectangular shape in cross section and re- ..ceives the pulpthrough the inlet 63 at the upper end and discharges through the chute64 at the-lower end. The air supply pipe 65 is connected to thehorizontal air pipe 66 atthe upper end and the, nozzle pipes 67 extenddownwardly into the tank 62 and have the perforations 68 through whichthe compressed air flows into of the shafts 72 which rotate freely intheir bearings.

The provision of a primary mixer, bleaching liquor supply, hot Waterfeed and washer and thickener is the same as for the rotatable aerator.

In the operation of this plant the bleaching liquor and hot water arefed separately and coincidently into the mixerwhich stirs the dense massof pulp fed thereinto, so that the pulp and the bleaching liquor get aprimary mixing aided by the heated water, which acts not only as avehicle in promoting the flow of the bleach but brings the temperatureup to a proper degree for efficiency in the treatment.

The treated pulp progresses to the larger end of the mixer and passesout through the chute to the aerating tank which fills up and is keptlevelled by the upper rotating arm. Intermediately the nozzle rotatesthrough the mass and delivers air under pressure,

thereby making the pulp porous allowing a perfect distribution of theair the same driving out the decomposition gases.

It will be thus seen that facilities are provided for the thoroughdistribution of the bleach in the mass and for the expulsion ofimpurities tending to promote decomposi-' tion.

The aerated npulp is disturbed at the bottom ofthe ta by the scraper,which aids the discharge through the central outlet into the chute, andfrom this chute it enters a.

combined washer-Hand thickener and if finished passes on to the stockchest, but in most plants it will pass into another washer andthickener, then to another mixing tank, continuing this in as manystages as may be found necessary. The bleaching liquor and hot water arefed through feed pipes to each one of the mixers receiving the pulp froma washer and thickener as the operation is just the same at each stageand is repeated until the condition of the pulp is satisfactory.

In the rectangular tank the operation only differs in regard to the feedof air and the grate means for facilitating the discharge.

The apparatus described is mostly for use in the pulp industry though itmay-be used in other arts, no doubt with advantage and economy to theuser. Further it is of considerable importance to the pulp indust inregard to refining methods especially w ere it is desirable to introduceother'chemicals. It is not possible to detail all the ossible uses andit is sufiicient to say that t e-mere through said upper end and throughsaid shaft.

fact that one use is described herein will in no way confine theinvention to any particular purpose.

What I claim is 1. In a bleaching plant, a plurality of vertical casingshaving inlet and discharge passages through the upper and lower ends respectively, said casings being indirectly connected with one another andmeans for feeding material to the upper casing continually during theoperation at a rate consistent with the constant discharge of thelowermost casing.

2. In a plant for bleaching pur uses, a tower having contracted passagesor inlet and discharge through the respective ends and having a chuteinlet and achute outlet formed to regulate the speed of the passingmaterial within the tower, and a scavenging member within the towerconnected to a compressed fluid supply.

3. In a bleaching apparatus, a bleaching tower having a permanent inletat the upper end and having a contracted discharge opening at the lowerend and a hollow shaft forming an air chamber and extendin saiddischarge opening and suitably driven.

4. In a bleaching apparatus, a bleaching tower having inlet anddischarge passages through the respective ends, a hollow shaft suitablydriven and extending through said ends and having a jet communicatingwith the interior and rotated within the tower and adapted to be fedthrough said shaft with a fluid under pressure connected with 5. In ableaching apparatus, a bleaching tower having inlet and dischargepassages through the respective ends, bearlngs beyond said ends, ahollow shaft journaled in said bearings and having an outlet within thetower, a compressed air tank connected to said shaft, a hollow armforming a nozzle and having a plurality of jets and a hub mountedfixedly on said shaft over said out-. let and means for driving saidshaft.

6. In a bleaching apparatus, a bleaching tower having a chute inlet andhopper out let, a shaft centrally situated in said tower and journaledin bearings above and below, having an outlet intermediate of the heightof the tower and forming an air passage, a crooked hollow arm having jetopenings therealong and ahub encircling said shaft and fixedly securedthereto over said outlet, an air inlet connected to said shaft and"means for rotating the latter.

feed inlets for water and bleaching agent, and a rotating separator forreducing the bundles to exposed fibers for impregnation and fixing thedensity of the material constantly passing through.

8. In a plant for bleaching purposes, a chain of vertical towersindirectly connected and fed with material from the upper end and havingfeed inlets and discharge outlets adapted to cause in each tower slowly'of the towers and means for supplying fluid under pressure to the hollowshaft.

10. In a bleaching apparatus, a vessel having a hopper bottomcentralizing a discharge opening and a chute from said discharge openingand a rotatable hollow air shaft connected to a compressed air supplyand carrying a scraper arm rotatable around said hopper bottom, a nozzlearm having a plurality of jets communicating with the interior of saidshaft and a levelling arm towards the up er end. i

11. In a bleac ing apparatus, a plurality of towers arranged one abovethe other and having free inlets through upper ends adapted to receivethe falling material and converging lower discharge ends leading tochutes formin diverting channels, intermediate vessels introduced in thecommunications between the said towers, fixed bearings above and belowthe topmost and lowermost towers, a shaft journalled in said bearingsand extending through all towers and forming an air'passage, means forfeeding air to said shaft, means for delivering air from said shaftwithin the towers and means for driving said shaft.

12. In a bleaching apparatus, a plurality of towers in verticalalignment having lower open ends and diverting channels therefrom,

communicating vessels between said towers, a vertical shaft runningcentrally through each tower and being journalled above and below thetowers and suitably driven and forming an air passage into said towersand levelling arms, air arms and scraper arms carried by said shafts inthe towers.

Signed at Montreal, Canada, this 19th day of November 1924.

CARL BUSCH THORNE.

